Radiant is an El Segundo, CA-based startup building the world’s first mass-produced, portable nuclear microreactors. The company’s first reactor, Kaleidos, is a 1-megawatt, fail-safe microreactor that can be transported anywhere power is needed and run for up to 5 years without refueling. Portable nuclear power with rapid-deploy capability can replace similar-sized diesel generators and provide critical asset support for hospitals, data centers, remote sites, and military bases. Radiant’s unique, practical approach to nuclear development leverages modern software engineering to rapidly deliver safe, factory-built microreactors that use existing, well-qualified materials. Founded in 2020, Radiant is on track to test its first reactor at the Idaho National Laboratory this summer, with initial customer deliveries beginning in 2028.
About the Role
Radiant is seeking a highly motivated Mechanical Engineer, Fluids Systems to help own critical Kaleidos fluid systems from preliminary design through build and production. These systems include the primary loop subsystems and power conversion loop, serving to convert heat from the reactor core into electrical power. You will be responsible for the following: trade studies, component selection, thermal hydraulic analysis, piping design, vendor selection, assembly, and testing. You will have an instrumental impact of fueling the first new commercial reactor design in over 50 years by 2026.
Responsibilities & Duties:
Help own end-to-end engineering of fluid systems and components, including compressors, valves, and heat exchangers.
Perform thermal and fluids analysis to drive design decisions, verify system performance, and ensure structural integrity using first-principle hand calculations and finite element tools.
Perform trade studies to optimize system and meet program requirements.
Develop and execute manufacturing/assembly instructions and test plans.
Create and manage a Bill-Of-Materials (BOM).
Find and develop suppliers for all components.
Own subassembly design, manufacturing, and test schedules.
Own risk analysis (FMEA) for subsystems.
Collect requirements, provide expertise and feedback to engineers in other functional areas via clear, constructive communication.
Required Qualifications & Skills:
Bachelor’s degree from an accredited institution in Mechanical, Materials, Aeronautical, Civil or Structural Engineering.
Experience with fluid system architecture design.
Experience in designing, building, and testing fluids systems.
Proficient knowledge in fluid dynamics and thermodynamics.
Proficient knowledge of heat exchanger design and analysis methods.
Desired Qualifications & Skills:
Knowledge of thermodynamic power cycles.
Prior experience with fluid system modeling via Matlab/Python.
Experienced in design for manufacturability and ramping up hardware build in a production environment.
Experienced in designing and operating test stands.
Takes extreme ownership of work and a high degree of responsibility.
Excellent communication across multidisciplinary teams.
Prior nuclear experience in not required for this role.
Benefits and Perks
Stock: Substantial incentive stock plan for all full-time employees.
Medical: 100% up to base silver level plan for employee + 50% dependents, offers up to Platinum plans.
One Medical: Sponsored memberships for employees and their dependents.
Vision: 100% top tier plan coverage + 50% for dependents.
Dental: 100% top tier plan coverage, orthodontia extra, 50% for dependents.
Voluntary life, accident, hospital, critical illness, commuter and FSA/HSA are offered as employee contributed benefits.
8-weeks of paid parental leave for all parents. Additional paid pregnancy leave for CA employees.
Daily catered lunch. Free snacks and drinks.
Flexible PTO policy. Remote workday allocation.
Company and team-bonding events, happy hours and in-person camaraderie.
Beautiful El Segundo headquarters close to the Pacific Ocean.
Total Compensation and Benefits Radiant compensates people for impact and invests in those who continue to raise the bar. Radiant’s new hire compensation package includes base salary, substantial equity grants, and comprehensive health benefits. Total compensation and level are determined through a rigorous evaluation of interview performance, experience, education, and qualifications, and are designed to support continued growth as scope, responsibility, and impact expand at Radiant.
The best of today’s advanced reactor builders don’t wait for job postings. They join the winning team. If that’s you, contact us directly for immediate opportunities: recruiting@radiantnuclear.com.
We are an equal opportunity employer and all qualified applicants will receive consideration for employment without regard to race, color, religion, sex, sexual orientation, gender identity or expression, pregnancy, age, national origin, disability status, genetic information, protected veteran status, or any other characteristic protected by law.
This position involves access to technology that is subject to U.S. export controls. Any job offer made will be contingent upon the applicant’s capacity to serve in compliance with U.S. export controls.
Listed by Radiant for a position based in the United States. Employers on this board attest they are hiring domestically.
ABOUT RADIANT
Radiant is an El Segundo, CA-based startup building the world’s first mass-produced, portable nuclear microreactors. The company’s first reactor, Kaleidos, is a 1-megawatt, fail-safe microreactor that can be transported anywhere power is needed and run for up to 5 years without refueling. Portable nuclear power with rapid-deploy capability can replace similar-sized diesel generators and provide critical asset support for hospitals, data centers, remote sites, and military bases. Radiant’s unique, practical approach to nuclear development leverages modern software engineering to rapidly deliver safe, factory-built microreactors that use existing, well-qualified materials. Founded in 2020, Radiant is on track to test its first reactor at the Idaho National Laboratory this summer, with initial customer deliveries beginning in 2028.
ABOUT THE ROLE
We are seeking a Senior Test Engineer to design and implement mission-critical procedures for reactor operators managing our groundbreaking nuclear microreactor technology. This role offers a rare opportunity to bridge engineering, operations, and human factors in a highly technical and fast-paced environment. You will collaborate with a multidisciplinary team to translate complex hardware and software designs into clear, executable, and DOE or NRC compliant procedures. Your work will ensure that Reactor Operators (ROs) and Senior Reactor Operators (SROs) can efficiently and safely execute test, commissioning, and operational activities.
This position goes beyond traditional systems engineering - you will also gain hands-on experience as a Reactor Operator (RO), directly influencing the development of operational software, procedures, and future reactor designs.
Responsibilities & Duties:
- Qualify as an operator to gain firsthand experience, ensuring procedures align with real-world execution.
- Collaborate closely with engineers to improve operator interfaces, procedural workflows, and software tools.
- Support testing and iterative improvements of digital twin scenarios, operator systems, and human-machine interfaces.
- Ensure compliance with DOE and NRC standards, maintaining strict formatting, clarity, and usability in procedural documentation.
- Develop and refine operational procedures that integrate both software and hardware-in-the-loop testing.
Required Qualifications & Skills:
- 6-7+ years of full-time professional experience in engineering problem-solving, including system design, analysis, or testing.
- Proficiency in managing or optimizing complex hardware and software processes for testing and operations.
- Ability to apply first principles thinking to solve problems and make decisions in uncertain or ambiguous situations.
- Background in highly regulated industries (e.g., nuclear, aerospace, aviation, maritime).
Desired Qualifications & Skills:
- Prior experience working as an operator in nuclear environments (e.g., nuclear energy, naval reactors, or radiation-controlled facilities), with familiarity in safety protocols, regulatory compliance, and high-reliability operations
- 2+ years of full-time nuclear operations experience.
- Licensed as Senior Reactor Operator or Naval equivalent.
- Hands-on experience in developing technical procedures, human factors engineering, or operational interface design.
- Prior operations background such as mission control room operator.
- Proficiency in Python, UNIX, for procedure testing within the simulator environments.
- Experience with human factors and user-centered instructions for operational workflows.
Additional Requirements:
- Must be willing to work extended hours and weekends as necessary to accomplish our mission.
- Must work 100% onsite at El Segundo HQ.
- Willingness to travel 50% - 60% of the time as needed for projects.
BENEFITS AND PERKS
- Stock: Substantial incentive stock plan for all full-time employees.
- Medical: 100% up to base silver level plan for employee + 50% dependents, offers up to Platinum plans.
- One Medical: Sponsored memberships for employees and their dependents.
- Vision: 100% top tier plan coverage + 50% for dependents.
- Dental: 100% top tier plan coverage, orthodontia extra, 50% for dependents.
- Voluntary life, accident, hospital, critical illness, commuter and FSA/HSA are offered as employee contributed benefits.
- 8-weeks of paid parental leave for all parents. Additional paid pregnancy leave for CA employees.
- Daily catered lunch. Free snacks and drinks.
- Flexible PTO policy. Remote workday allocation.
- Company and team-bonding events, happy hours and in-person camaraderie.
- Beautiful El Segundo headquarters close to the Pacific Ocean.
Total Compensation and Benefits
Radiant compensates people for impact and invests in those who continue to raise the bar. Radiant’s new hire compensation package includes base salary, substantial equity grants, and comprehensive health benefits. Total compensation and level are determined through a rigorous evaluation of interview performance, experience, education, and qualifications, and are designed to support continued growth as scope, responsibility, and impact expand at Radiant.
The best of today’s advanced reactor builders don’t wait for job postings. They join the winning team. If that’s you, contact us directly for immediate opportunities: recruiting@radiantnuclear.com.
We are an equal opportunity employer and all qualified applicants will receive consideration for employment without regard to race, color, religion, sex, sexual orientation, gender identity or expression, pregnancy, age, national origin, disability status, genetic information, protected veteran status, or any other characteristic protected by law.
This position involves access to technology that is subject to U.S. export controls. Any job offer made will be contingent upon the applicant’s capacity to serve in compliance with U.S. export controls.
Listed by Radiant for a position based in the United States. Employers on this board attest they are hiring domestically.
Engineering
100 days ago
Mechanical Engineer, Fluid Systems - 2026 New Graduate
ABOUT RADIANT
Radiant is an El Segundo, CA-based startup building the world’s first mass-produced, portable nuclear microreactors. The company’s first reactor, Kaleidos, is a 1-megawatt, fail-safe microreactor that can be transported anywhere power is needed and run for up to 5 years without refueling. Portable nuclear power with rapid-deploy capability can replace similar-sized diesel generators and provide critical asset support for hospitals, data centers, remote sites, and military bases. Radiant’s unique, practical approach to nuclear development leverages modern software engineering to rapidly deliver safe, factory-built microreactors that use existing, well-qualified materials. Founded in 2020, Radiant is on track to test its first reactor at the Idaho National Laboratory this summer, with initial customer deliveries beginning in 2028.
ABOUT THE ROLE
Radiant is seeking a highly motivated Mechanical Engineer, Fluids Systems to help own critical Kaleidos fluid systems from preliminary design through build and production. These systems include the primary loop subsystems and power conversion loop, serving to convert heat from the reactor core into electrical power. You will be responsible for the following: trade studies, component selection, thermal hydraulic analysis, piping design, vendor selection, assembly, and testing. You will have an instrumental impact of fueling the first new commercial reactor design in over 50 years by 2026.
Responsibilities & Duties:
- Help own end-to-end engineering of fluid systems and components, including compressors, valves, and heat exchangers.
- Perform thermal and fluids analysis to drive design decisions, verify system performance, and ensure structural integrity using first-principle hand calculations and finite element tools.
- Perform trade studies to optimize system and meet program requirements.
- Develop and execute manufacturing/assembly instructions and test plans.
- Create and manage a Bill-Of-Materials (BOM).
- Find and develop suppliers for all components.
- Own subassembly design, manufacturing, and test schedules.
- Own risk analysis (FMEA) for subsystems.
- Collect requirements, provide expertise and feedback to engineers in other functional areas via clear, constructive communication.
Required Qualifications & Skills:
- Bachelor’s degree from an accredited institution in Mechanical, Materials, Aeronautical, Civil or Structural Engineering.
- Experience with fluid system architecture design.
- Experience in designing, building, and testing fluids systems.
- Proficient knowledge in fluid dynamics and thermodynamics.
- Proficient knowledge of heat exchanger design and analysis methods.
Desired Qualifications & Skills:
- Knowledge of thermodynamic power cycles.
- Prior experience with fluid system modeling via Matlab/Python.
- Experienced in design for manufacturability and ramping up hardware build in a production environment.
- Experienced in designing and operating test stands.
- Takes extreme ownership of work and a high degree of responsibility.
- Excellent communication across multidisciplinary teams.
- Prior nuclear experience in not required for this role.
BENEFITS AND PERKS
- Stock: Substantial incentive stock plan for all full-time employees.
- Medical: 100% up to base silver level plan for employee + 50% dependents, offers up to Platinum plans.
- One Medical: Sponsored memberships for employees and their dependents.
- Vision: 100% top tier plan coverage + 50% for dependents.
- Dental: 100% top tier plan coverage, orthodontia extra, 50% for dependents.
- Voluntary life, accident, hospital, critical illness, commuter and FSA/HSA are offered as employee contributed benefits.
- 8-weeks of paid parental leave for all parents. Additional paid pregnancy leave for CA employees.
- Daily catered lunch. Free snacks and drinks.
- Flexible PTO policy. Remote workday allocation.
- Company and team-bonding events, happy hours and in-person camaraderie.
- Beautiful El Segundo headquarters close to the Pacific Ocean.
Total Compensation and Benefits
Radiant compensates people for impact and invests in those who continue to raise the bar. Radiant’s new hire compensation package includes base salary, substantial equity grants, and comprehensive health benefits. Total compensation and level are determined through a rigorous evaluation of interview performance, experience, education, and qualifications, and are designed to support continued growth as scope, responsibility, and impact expand at Radiant.
The best of today’s advanced reactor builders don’t wait for job postings. They join the winning team. If that’s you, contact us directly for immediate opportunities: recruiting@radiantnuclear.com.
We are an equal opportunity employer and all qualified applicants will receive consideration for employment without regard to race, color, religion, sex, sexual orientation, gender identity or expression, pregnancy, age, national origin, disability status, genetic information, protected veteran status, or any other characteristic protected by law.
This position involves access to technology that is subject to U.S. export controls. Any job offer made will be contingent upon the applicant’s capacity to serve in compliance with U.S. export controls.
Listed by Radiant for a position based in the United States. Employers on this board attest they are hiring domestically.
General
101 days ago
Director of Regulatory Affairs
Radiant · Washington, D.C., Washington, D.C., United States
ABOUT RADIANT
Radiant is an El Segundo, CA-based startup building the world’s first mass-produced, portable nuclear microreactors. The company’s first reactor, Kaleidos, is a 1-megawatt, fail-safe microreactor that can be transported anywhere power is needed and run for up to 5 years without refueling. Portable nuclear power with rapid-deploy capability can replace similar-sized diesel generators and provide critical asset support for hospitals, data centers, remote sites, and military bases. Radiant’s unique, practical approach to nuclear development leverages modern software engineering to rapidly deliver safe, factory-built microreactors that use existing, well-qualified materials. Founded in 2020, Radiant is on track to test its first reactor at the Idaho National Laboratory this summer, with initial customer deliveries beginning in 2028.
About The Role
Radiant is seeking a highly engaging and effective leader for our regulatory and licensing team. The Director of Regulatory Affairs will oversee licensing engagement, strategy, process, and execution with the U.S. Nuclear Regulatory Commission (NRC). You will play a pivotal role in driving Kaleidos’ development timeline, successful demonstration, and future commercialization. The ideal candidate is experienced working with government agencies and officials in risk-informed regulations, is determined to execute on how things should be done vs. how they’ve always been done and can engage deeply with our engineering organization to produce a foundationally safe product rather than one that simply checks regulatory boxes. The ideal candidate will foster a healthy team culture, provide support and clarity where needed, and come in with a player-coach mindset. We are looking for someone who is excited to put the first microreactor on the market and provide clean, reliable energy to remote areas around the world. This role reports to our Chief Nuclear Officer and is based in Washington, DC.
Responsibilities and Duties:
- Provide licensing and regulatory leadership and strategic guidance to a high performing team.
- Craft a modern regulatory strategy based in sound engineering principles with input from executives, our board of directors, and industry experts that brings the safest product to market the fastest.
- Own end- to- end licensing execution efforts establishing strict principle-based standards while promoting streamlined, modern approaches to regulatory interactions.
- Facilitate collaborative and cohesive partnerships with internal stakeholders and external regulatory and governing bodies to drive desirable results. Includes attending in-person NRC visits, online meetings, and industry-related social events.
- Ensure the completeness, timeliness, and quality of licensing and regulatory submissions.
- Integrate our regulatory process with technical teams to meet quality assurance and regulatory standards.
Required Skills and Qualifications:
- Bachelor’s degree at an accredited institution in engineering discipline.
- 8+ years of industry experience working on nuclear regulatory and licensing efforts.
- 2+ years leading a team.
- Ability to travel and attend in-person meetings.
Desired Skills and Qualifications:
- Direct experience with the NRC.
- Experience in 10 CFR 50 and 10 CFR 70.
- Demonstrated ability work with a technical team to take complex information and simplify it for non-technical audiences.
- Intrinsic motivation to forge through decades of regulatory precedence with a creative approach.
- Strategic aptitude to bring together various complicated threads into a simple throughline.
- Outstanding written and verbal communications skills, as well as building relationships with internal and external stakeholders.
- Demonstrated ability to create coalitions and partnerships with other leaders in nuclear industry.
Additional Requirements:
- Must be willing to work extended hours and weekends as necessary to accomplish our mission.
- Must work 100% onsite at Washington, DC HQ.
BENEFITS AND PERKS
- Stock: Substantial incentive stock plan for all full-time employees.
- Medical: 100% up to base silver level plan for employee + 50% dependents, offers up to Platinum plans.
- One Medical: Sponsored memberships for employees and their dependents.
- Vision: 100% top tier plan coverage + 50% for dependents.
- Dental: 100% top tier plan coverage, orthodontia extra, 50% for dependents.
- Voluntary life, accident, hospital, critical illness, commuter and FSA/HSA are offered as employee contributed benefits.
- 8-weeks of paid parental leave for all parents. Additional paid pregnancy leave for CA employees.
- Daily catered lunch. Free snacks and drinks.
- Flexible PTO policy. Remote workday allocation.
- Company and team-bonding events, happy hours and in-person camaraderie.
- Beautiful El Segundo headquarters close to the Pacific Ocean.
Total Compensation and Benefits
Radiant compensates people for impact and invests in those who continue to raise the bar. Radiant’s new hire compensation package includes base salary, substantial equity grants, and comprehensive health benefits. Total compensation and level are determined through a rigorous evaluation of interview performance, experience, education, and qualifications, and are designed to support continued growth as scope, responsibility, and impact expand at Radiant.
The best of today’s advanced reactor builders don’t wait for job postings. They join the winning team. If that’s you, contact us directly for immediate opportunities: recruiting@radiantnuclear.com.
We are an equal opportunity employer and all qualified applicants will receive consideration for employment without regard to race, color, religion, sex, sexual orientation, gender identity or expression, pregnancy, age, national origin, disability status, genetic information, protected veteran status, or any other characteristic protected by law.
This position involves access to technology that is subject to U.S. export controls. Any job offer made will be contingent upon the applicant’s capacity to serve in compliance with U.S. export controls.
Listed by Radiant for a position based in the United States. Employers on this board attest they are hiring domestically.
ABOUT RADIANT
Radiant is an El Segundo, CA-based startup building the world’s first mass-produced, portable nuclear microreactors. The company’s first reactor, Kaleidos, is a 1-megawatt, fail-safe microreactor that can be transported anywhere power is needed and run for up to 5 years without refueling. Portable nuclear power with rapid-deploy capability can replace similar-sized diesel generators and provide critical asset support for hospitals, data centers, remote sites, and military bases. Radiant’s unique, practical approach to nuclear development leverages modern software engineering to rapidly deliver safe, factory-built microreactors that use existing, well-qualified materials. Founded in 2020, Radiant is on track to test its first reactor at the Idaho National Laboratory this summer, with initial customer deliveries beginning in 2028.
ABOUT THE ROLE
Radiant is seeking a Principal Embedded Software Engineer to set the technical direction for embedded software across instrumentation and control (I&C) systems. You will define architecture, establish engineering standards, and personally drive the development of mission-critical, highly performant embedded systems that interface with sensors and actuators at the heart of a first-of-its-kind reactor design. The ideal candidate thrives in ambiguous early-stage environments, can make high-consequence technical decisions with incomplete information, and leaves a lasting organizational imprint through the systems and culture they build. You will have the opportunity to shape the embedded software foundation of the first commercialized portable nuclear microreactor, technology that will redefine how the world accesses clean, reliable power.
RESPONSIBILITIES AND DUTIES
- Define and own the embedded software architecture for I&C systems, establishing patterns and standards that scale across the full program lifecycle.
- Lead design and development of reliable, fault-tolerant embedded software for production hardware operating in demanding environments.
- Develop and bring up new drivers for I&C hardware across a range of sensing and actuation subsystems.
- Serve as the senior technical voice in design reviews, setting the bar for rigor, surfacing systemic risks, and driving decisions that span multiple subsystems and teams.
- Own the full engineering lifecycle, from architecture through test, build, and field implementation, and set expectations for how the team executes that lifecycle.
- Establish robust hardware and software testing frameworks, validation methodology, and documentation standards that meet rigorous safety requirements.
- Mentor embedded engineers across the team; model technical excellence and engineering judgment.
- Partner with electrical, controls, and hardware engineering leadership to align on cross-disciplinary interfaces and constraints.
REQUIRED QUALIFICATIONS AND SKILLS
- Bachelor's degree in computer engineering, computer science, electrical engineering, or a related field.
- 8+ years of industry experience in embedded software, including significant ownership of system-level architecture decisions.
- Demonstrated experience driving architecture across complex, multi-subsystem embedded programs, not just feature ownership.
- Hands-on experience with an RTOS (Zephyr, NuttX, ThreadX, etc.), including low-level bring-up and porting.
- Deep proficiency in embedded C/C++.
- Track record of influencing technical direction beyond your immediate team, through documentation, standards, or cross-functional alignment.
- Strong communicator capable of driving consensus across engineering, program, and leadership stakeholders.
DESIRED QUALIFICATIONS AND SKILLS
- Experience with Zephyr RTOS at an architectural or maintainer level.
- Experience working with Simulink Autocode C++ export in a production context.
- Experience with CMake in large, multi-target embedded builds.
- Proficiency in reading and interpreting hardware schematics; ability to debug at the hardware/software boundary.
- Experience in safety-critical or high-reliability domains (aerospace, defense, medical, nuclear, or industrial).
ADDITIONAL REQUIREMENTS
- Must be willing to work extended hours and weekends as necessary to accomplish our mission.
- Must work 100% onsite at El Segundo HQ.
BENEFITS AND PERKS
- Stock: Substantial incentive stock plan for all full-time employees.
- Medical: 100% up to base silver level plan for employee + 50% dependents, offers up to Platinum plans.
- One Medical: Sponsored memberships for employees and their dependents.
- Vision: 100% top tier plan coverage + 50% for dependents.
- Dental: 100% top tier plan coverage, orthodontia extra, 50% for dependents.
- Voluntary life, accident, hospital, critical illness, commuter and FSA/HSA are offered as employee contributed benefits.
- 8-weeks of paid parental leave for all parents. Additional paid pregnancy leave for CA employees.
- Daily catered lunch. Free snacks and drinks.
- Flexible PTO policy. Remote workday allocation.
- Company and team-bonding events, happy hours and in-person camaraderie.
- Beautiful El Segundo headquarters close to the Pacific Ocean.
Total Compensation and Benefits
Radiant compensates people for impact and invests in those who continue to raise the bar. Radiant’s new hire compensation package includes base salary, substantial equity grants, and comprehensive health benefits. Total compensation and level are determined through a rigorous evaluation of interview performance, experience, education, and qualifications, and are designed to support continued growth as scope, responsibility, and impact expand at Radiant.
The best of today’s advanced reactor builders don’t wait for job postings. They join the winning team. If that’s you, contact us directly for immediate opportunities: recruiting@radiantnuclear.com.
We are an equal opportunity employer and all qualified applicants will receive consideration for employment without regard to race, color, religion, sex, sexual orientation, gender identity or expression, pregnancy, age, national origin, disability status, genetic information, protected veteran status, or any other characteristic protected by law.
This position involves access to technology that is subject to U.S. export controls. Any job offer made will be contingent upon the applicant’s capacity to serve in compliance with U.S. export controls.
Listed by Radiant for a position based in the United States. Employers on this board attest they are hiring domestically.
ABOUT RADIANT
Radiant is an El Segundo, CA-based startup building the world’s first mass-produced, portable nuclear microreactors. The company’s first reactor, Kaleidos, is a 1-megawatt, fail-safe microreactor that can be transported anywhere power is needed and run for up to 5 years without refueling. Portable nuclear power with rapid-deploy capability can replace similar-sized diesel generators and provide critical asset support for hospitals, data centers, remote sites, and military bases. Radiant’s unique, practical approach to nuclear development leverages modern software engineering to rapidly deliver safe, factory-built microreactors that use existing, well-qualified materials. Founded in 2020, Radiant is on track to test its first reactor at the Idaho National Laboratory this summer, with initial customer deliveries beginning in 2028.
ABOUT THE ROLE
Radiant is seeking a highly motivated Mechanical Engineer, Fluids Systems to own critical Kaleidos fluid systems from preliminary design through build and production. These systems include the primary loop subsystems and power conversion loop, serving to convert heat from the reactor core into electrical power. You will be responsible for the following: trade studies, component selection, thermal hydraulic analysis, piping design, vendor selection, assembly, and testing. You will have an instrumental impact of fueling the first new commercial reactor design in over 50 years by 2026.
Responsibilities & Duties:
- Own end-to-end engineering of fluid systems and components, including compressors, valves, and heat exchangers.
- Perform complex thermal and fluids analysis to drive design decisions, verify system performance, and ensure structural integrity using first-principle hand calculations and finite element tools.
- Perform trade studies to optimize system and meet program requirements.
- Develop and execute manufacturing/assembly instructions and test plans.
- Create and manage a Bill-Of-Materials (BOM).
- Find and develop suppliers for all components.
- Own subassembly design, manufacturing, and test schedules.
- Own risk analysis (FMEA) for subsystems.
- Collect requirements, provide expertise and feedback to engineers in other functional areas via clear, constructive communication.
Required Qualifications & Skills:
- Bachelor’s degree from an accredited institution in Mechanical, Materials, Aeronautical, Civil or Structural Engineering.
- Experience with fluid system architecture design.
- 2+ years of experience in designing, building, and testing fluids systems.
- Proficient knowledge in fluid dynamics and thermodynamics.
- Proficient knowledge of heat exchanger design and analysis methods.
Desired Qualifications & Skills:
- Knowledge of thermodynamic power cycles.
- Prior experience with designing piping system for thermal growth using hand calculations and FEA tools.
- Experience with process piping design and testing codes, such as ASME B31.3 and ASME PCC-2.
- Prior experience with fluid system modeling via Matlab/Python.
- Experienced in design for manufacturability and ramping up hardware build in a production environment.
- Experienced in designing and operating test stands.
- Takes extreme ownership of work and a high degree of responsibility.
- Excellent communication across multidisciplinary teams.
- Prior nuclear experience in not required for this role.
Additional Requirements:
- Must be willing to work extended hours and weekends as necessary to accomplish our mission.
- Must work 100% onsite at El Segundo HQ.
BENEFITS AND PERKS
- Stock: Substantial incentive stock plan for all full-time employees.
- Medical: 100% up to base silver level plan for employee + 50% dependents, offers up to Platinum plans.
- One Medical: Sponsored memberships for employees and their dependents.
- Vision: 100% top tier plan coverage + 50% for dependents.
- Dental: 100% top tier plan coverage, orthodontia extra, 50% for dependents.
- Voluntary life, accident, hospital, critical illness, commuter and FSA/HSA are offered as employee contributed benefits.
- 8-weeks of paid parental leave for all parents. Additional paid pregnancy leave for CA employees.
- Daily catered lunch. Free snacks and drinks.
- Flexible PTO policy. Remote workday allocation.
- Company and team-bonding events, happy hours and in-person camaraderie.
- Beautiful El Segundo headquarters close to the Pacific Ocean.
Total Compensation and Benefits
Radiant compensates people for impact and invests in those who continue to raise the bar. Radiant’s new hire compensation package includes base salary, substantial equity grants, and comprehensive health benefits. Total compensation and level are determined through a rigorous evaluation of interview performance, experience, education, and qualifications, and are designed to support continued growth as scope, responsibility, and impact expand at Radiant.
The best of today’s advanced reactor builders don’t wait for job postings. They join the winning team. If that’s you, contact us directly for immediate opportunities: recruiting@radiantnuclear.com.
We are an equal opportunity employer and all qualified applicants will receive consideration for employment without regard to race, color, religion, sex, sexual orientation, gender identity or expression, pregnancy, age, national origin, disability status, genetic information, protected veteran status, or any other characteristic protected by law.
This position involves access to technology that is subject to U.S. export controls. Any job offer made will be contingent upon the applicant’s capacity to serve in compliance with U.S. export controls.
Listed by Radiant for a position based in the United States. Employers on this board attest they are hiring domestically.
Radiant is an El Segundo, CA-based startup building the world’s first mass-produced, portable nuclear microreactors. The company’s first reactor, Kaleidos, is a 1-megawatt, fail-safe microreactor that can be transported anywhere power is needed and run for up to 5 years without refueling. Portable nuclear power with rapid-deploy capability can replace similar-sized diesel generators and provide critical asset support for hospitals, data centers, remote sites, and military bases. Radiant’s unique, practical approach to nuclear development leverages modern software engineering to rapidly deliver safe, factory-built microreactors that use existing, well-qualified materials. Founded in 2020, Radiant is on track to test its first reactor at the Idaho National Laboratory this summer, with initial customer deliveries beginning in 2028.
About the Role
As a Project Developer in Radiant’s Commercial organization, your job is to deliver reactors to our contracted customers. You will own the end-to-end process, serving as the single point of accountability from contract award through reactor delivery. You will work with the customer’s site team, ensure compliance with contract requirements, and manage the project from local permitting through electrical interconnection. Within Radiant, your key points of contact will be the licensing, state engagement, engineering, and manufacturing teams. The projects you manage will be successful if they are delivered on time and on budget.
Responsibilities & Duties:
Ensure the successful delivery of projects under contract for deployment at government and commercial customer sites.
Manage the timely execution of regulatory, engineering, and siting deliverables.
Drive contract milestones to completion.
Own deliverable creation and partner across the team where support is necessary.
When working with our government customers, act as the primary interface with contracting officers, program offices, installation personnel, and end users.
When working with our commercial customers, act as the primary interface with project sponsors, site leads, and operations personnel.
Architect and maintain integrated master schedules and cost baselines, ensuring internal teams and subcontractors are aligned to contract obligations.
Manage contract compliance including reporting requirements and milestone billing; support negotiation of contract modifications and change orders.
Independently identify, assess, and drive resolution of programmatic risks and cross-functional dependencies.
Stand up and refine the project management processes, tools, and reporting cadence needed to provide clear visibility to company leadership and consistent milestone updates to customer partners.
Required Qualifications & Skills:
3-5+ years of experience in energy project development, project management, or a related field.
Experience managing programs requiring the delivery of complex capital equipment or large scale industrial systems.
Strong command of integrated master scheduling.
Proven ability to manage programs with significant technical complexity, multiple parallel work streams, and cross-functional dependencies.
Demonstrated experience managing and reporting project financial performance, budgets, scopes, and schedules.
U.S. citizenship required (absolutely no exceptions); ability to obtain and maintain a security clearance.
Ability to travel ~10-20%.
Desired Qualifications & Skills:
Familiarity with electric power infrastructure projects and knowledge of business issues associated with power delivery services.
Experience supporting U.S. government contracts.
Direct working knowledge of FAR/DFARS compliance, government contract types (cost-plus, firm-fixed-price, time and materials), and federal reporting and audit requirements.
Active DoD security clearance.
Additional Requirements:
Must be willing to work extended hours and weekends as necessary to accomplish our mission.
Must work 100% onsite at El Segundo HQ.
Benefits and Perks
Stock: Substantial incentive stock plan for all full-time employees.
Medical: 100% up to base silver level plan for employee + 50% dependents, offers up to Platinum plans.
One Medical: Sponsored memberships for employees and their dependents.
Vision: 100% top tier plan coverage + 50% for dependents.
Dental: 100% top tier plan coverage, orthodontia extra, 50% for dependents.
Voluntary life, accident, hospital, critical illness, commuter and FSA/HSA are offered as employee contributed benefits.
8-weeks of paid parental leave for all parents. Additional paid pregnancy leave for CA employees.
Daily catered lunch. Free snacks and drinks.
Flexible PTO policy. Remote workday allocation.
Company and team-bonding events, happy hours and in-person camaraderie.
Beautiful El Segundo headquarters close to the Pacific Ocean.
Total Compensation and Benefits Radiant compensates people for impact and invests in those who continue to raise the bar. Radiant’s new hire compensation package includes base salary, substantial equity grants, and comprehensive health benefits. Total compensation and level are determined through a rigorous evaluation of interview performance, experience, education, and qualifications, and are designed to support continued growth as scope, responsibility, and impact expand at Radiant.
The best of today’s advanced reactor builders don’t wait for job postings. They join the winning team. If that’s you, contact us directly for immediate opportunities: recruiting@radiantnuclear.com.
We are an equal opportunity employer and all qualified applicants will receive consideration for employment without regard to race, color, religion, sex, sexual orientation, gender identity or expression, pregnancy, age, national origin, disability status, genetic information, protected veteran status, or any other characteristic protected by law.
This position involves access to technology that is subject to U.S. export controls. Any job offer made will be contingent upon the applicant’s capacity to serve in compliance with U.S. export controls.
Listed by Radiant for a position based in the United States. Employers on this board attest they are hiring domestically.
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